Tumors

A facial paralysis that begins insidiously and progresses in severity is characteristic of a tumor arising from the facial nerve or more commonly a tumor which arises from adjacent structures and secondarily invades the facial nerve.

The most common tumor affecting the facial nerve is one that arises within the parotid gland. All parotid tumors that cause a facial paralysis are malignant. Symptoms include a painful mass within the gland and a facial paralysis. Left untreated, these tumors can follow along adjacent nerves and enter the brain. They can also spread via metastases to the lungs. Treatment includes surgical excision of the parotid gland along with the involved facial nerve. A nerve graft is obtained either from the neck, arm or leg to replace the involved facial nerve. Occasionally it is necessary to follow the facial nerve into the middle ear in order to be sure the entire tumor is removed. Oftentimes, radiation therapy is also given after surgery. Following surgical resection and reconstruction of the facial nerve, some facial nerve recovery can be expected, however facial function can never hope to return to normal.

Benign and malignant tumors that arise within the area of the skull base can also secondarily affect facial nerve function. These include meningiomas, paragangliomas (glomus tumors), chondrosarcomas, and chordomas. Each has their unique set of problems related to the type of tumor and the extent of involvement.

Benign tumors that arise directly from the facial nerve are relatively uncommon. These schwannomas arise from the cells that produce myelin, the outer insulating layer of nerve fibers. They usually present initially with twitching of the face followed by weakness. These tumors are found more commonly within the bony canal that courses through the temporal bone. There as the tumor expands, it exerts pressure against the nerve. Treatment depends on the symptoms at presentation. If the facial nerve function appears normal or near normal, it may be wise to either follow these tumors with clinical exams and imaging studies or recommend surgical decompression. If there is rapid growth or if the facial function declines with time, surgery to remove the tumor with reconstruction of the nerve may be indicated. With reconstruction it is not possible to restore the facial function to normal. Some return of facial function can be anticipated.

Infrequently schwannomas can affect the facial nerve branches traveling through the parotid gland. Patients may present with weakness of that branch of the facial nerve. Because there is room for expansion, symptoms may not appear until the tumors are rather large.